Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 238 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.863 − 799 =
2. 2.847 − 477 =
3. 3.671 − 597 =
4. 4.960 − 598 =
5. 5.702 − 387 =
6. 6.210 − 139 =
7. 7.268 − 147 =
8. 8.931 − 417 =
9. 9.716 − 397 =
10. 10.597 − 577 =
11. 11.801 − 597 =
12. 12.656 − 397 =
13. 13.662 − 499 =
14. 14.804 − 597 =
15. 15.678 − 498 =
16. 16.652 − 399 =
17. 17.568 − 247 =
18. 18.562 − 319 =
19. 19.641 − 499 =
20. 20.923 − 477 =
21. 21.639 − 597 =
22. 22.890 − 498 =
23. 23.649 − 599 =
24. 24.944 − 148 =
25. 25.673 − 198 =
26. 26.907 − 697 =
27. 27.346 − 198 =
28. 28.211 − 178 =
29. 29.540 − 428 =
30. 30.385 − 117 =
31. 31.324 − 297 =
32. 32.782 − 288 =
33. 33.731 − 198 =
34. 34.547 − 527 =
35. 35.751 − 397 =
36. 36.401 − 177 =
37. 37.994 − 197 =
38. 38.720 − 208 =
39. 39.590 − 498 =
40. 40.329 − 298 =

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